CVE-2026-72522

libexpat before 2.8.3 has an out-of-bounds read and resultant infinite loop because low surrogates are treated the same as high surrogates during Unicode processing in the *_toUtf16 functions.

CVE-2026-72522 is fixed in 9 products on 1 platform, first by DEBIAN-CVE-2026-72522, released August 18, 2026. It is not reported as exploited. Patch Radar priority: Routine.

Routine
CVSS
6.2
Moderate
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0019
8th percentile

libexpat before 2.8.3 has an out-of-bounds read and resultant infinite loop because low surrogates are treated the same as high surrogates during Unicode processing in the *_toUtf16 functions.

Where it's fixed

ProductFixed inFixReleased
Linux
MozillaFirefox · opensuse-leap 16.0 153.5.0-160000.1.1 OPENSUSE-SU-2026:22139-1 Nov 7, 2026
MozillaFirefox · sles 15.6 153.5.0-150400.157.16.1 SUSE-SU-2026:4834-1 Nov 7, 2026
MozillaFirefox · sles 15.7 153.5.0-150400.157.16.1 SUSE-SU-2026:4834-1 Nov 7, 2026
MozillaFirefox · sles 16.0 153.5.0-160000.1.1 SUSE-SU-2026:24260-1 Nov 7, 2026
MozillaThunderbird · sles 15.7 153.5.0-150400.13.9.1 SUSE-SU-2026:4736-1 Nov 7, 2026
expat · Debian 12.15 (bookworm) 2.5.0-1+deb12u3 DEBIAN-CVE-2026-72522 Aug 18, 2026
expat · Debian 13.5 (trixie) 2.8.3-1~deb13u1 DEBIAN-CVE-2026-72522 Aug 18, 2026
expat · Debian 14 2.8.3-1 DEBIAN-CVE-2026-72522 Aug 18, 2026
expat · Ubuntu 18.04.6 LTS (bionic) 2.2.5-3ubuntu0.9+esm5 expat 2.2.5-3ubuntu0.9+esm5 Aug 20, 2026
expat · Ubuntu 20.04 LTS (focal) 2.2.9-1ubuntu0.8+esm3 expat 2.2.9-1ubuntu0.8+esm3 Aug 20, 2026
expat · Ubuntu 22.04.1 LTS (jammy) 2.4.7-1ubuntu0.9 expat 2.4.7-1ubuntu0.9 Aug 20, 2026
expat · Ubuntu 24.04.5 LTS (noble) 2.6.1-2ubuntu0.6 expat 2.6.1-2ubuntu0.6 Aug 20, 2026
expat · Ubuntu 26.04.1 LTS (resolute) 2.7.4-1ubuntu0.2 expat 2.7.4-1ubuntu0.2 Aug 20, 2026
expat · opensuse-leap 16.0 2.8.4-160000.1.1 OPENSUSE-SU-2026:21945-1 Sep 24, 2026
expat · sles 15.6 2.8.5-150400.3.40.1 SUSE-SU-2026:4623-1 Nov 7, 2026
expat · sles 15.7 2.8.5-150700.3.15.1 SUSE-SU-2026:4619-1 Nov 7, 2026
expat · sles 16.0 2.8.4-160000.1.1 SUSE-SU-2026:23912-1 Sep 24, 2026
firefox · amzn 2023 140.14.0-1.amzn2023.0.1 ALAS2023-2026-2105 Aug 31, 2026
firefox-debuginfo · amzn 2023 140.14.0-1.amzn2023.0.1 ALAS2023-2026-2105 Aug 31, 2026
firefox-debugsource · amzn 2023 140.14.0-1.amzn2023.0.1 ALAS2023-2026-2105 Aug 31, 2026
libexpat1 · Ubuntu 18.04.6 LTS (bionic) 2.2.5-3ubuntu0.9+esm5 libexpat1 2.2.5-3ubuntu0.9+esm5 Aug 20, 2026
libexpat1 · Ubuntu 20.04 LTS (focal) 2.2.9-1ubuntu0.8+esm3 libexpat1 2.2.9-1ubuntu0.8+esm3 Aug 20, 2026
libexpat1 · Ubuntu 22.04.1 LTS (jammy) 2.4.7-1ubuntu0.9 libexpat1 2.4.7-1ubuntu0.9 Aug 20, 2026
libexpat1 · Ubuntu 24.04.5 LTS (noble) 2.6.1-2ubuntu0.6 libexpat1 2.6.1-2ubuntu0.6 Aug 20, 2026
libexpat1 · Ubuntu 26.04.1 LTS (resolute) 2.7.4-1ubuntu0.2 libexpat1 2.7.4-1ubuntu0.2 Aug 20, 2026
python312 · sles 15.6 3.12.14-150600.3.68.1 SUSE-SU-2026:4534-1 Oct 6, 2026
python312-core · sles 15.6 3.12.14-150600.3.68.1 SUSE-SU-2026:4534-1 Oct 6, 2026

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